Lattice Kinetic Modeling of the Anisotropic Growth of Two- Dimensional Islands on Barite (001) Surface.

Abstract

In this paper, we present simulations of twodimensional islands on the barite (001) face. These simulations were performed with MMonCa, a computer code based on the kinetic Monte Carlo technique. Our results are in excellent agreement with previous in situ atomic force microscopy (AFM) observations. Indeed, MMonCa is able to precisely reproduce both the thickness and the characteristic fan shape of barite (001) two-dimensional islands, which is defined by two straight steps parallel to the ⟨120⟩ directions and a curved step connecting them. An addition, MMonCa also simulates the orientation reversal of islands in successive growth monolayers. Fundamental for the adequate reproduction of the shape of barite (001) islands is the introduction of an anisotropy factor for the incorporation of growth units into crystallographically nonequivalent step edges. The results presented in this paper demonstrate that the consideration of simple crystallographic and geometrical constraints can be enough to provide a consistent explanation for the development of complex nanotopographies during the growth of crystals.